SORGHUM OPTIMUM ECONOMIC POPULATION DENSITY UNDER RAINFED CONDITIONS

Abstract

In order to determine the best population density in the double row method of sowing and to compare it whit the traditional method in single row, this study was carried out in Río Bravo, Tamaulipas, during the fall-winter season of 1991-92. Two experiments were sown under rainfed conditions with the hybrid Pioneer 8244: one in single row and another in double row. Population densities ranged from 125 to 435 thousand plants/ha in the single row method, and from 187 to 625 thousand plants/ha in the double row
method. The results indicated that in both methods the increase in plant density increased significantly panicle exsertion and reduced panicle weight and number of grains per panicle. In the double row method, when the population density was increased, the panicle lenght and percentaje of plants with productive panicles were significantly reduced. In both methods, grain yield was statistically similar in a range of 187-562 thousand plants/ha. However, the population density that yielded the maximum retum rate was 187 thousand plants/ha in the single row case, while in the double row method, the density of 250 thousand plants/ha was economically the best.